Abstract

This paper provides a comprehensive overview of the development of a NuScale power module in the Modelica process model ecosystem at Idaho National Laboratory (INL) as part of the U.S. Department of Energy’s Office of Nuclear Energy Integrated Energy Systems (IES) program.

Model development has led to the creation of a dynamic NuScale module in the Modelica language that operates under natural circulation and is consistent with design parameters set forth in the design certification documentation for the Nuclear Regulatory Commission (NRC). Controllers have been developed that are consistent with controllers mentioned by NuScale design certification documents. While characteristic time constants may differ due to controller gains, the actual control actions of the system are consistent with NuScale prescribed actions. In addition to natural circulation and controllers, the NuScale power module includes hot channel calculations, reactivity control, and a pressurizer. Hot channel calculations include bulk fluid temperature, outer clad temperature, fuel centerline temperature, and departure from nuclear boiling ratios. Reactivity control incorporates moderator and fuel temperature feedback mechanisms, boron concentration, and control bank positions. A pressurizer with sprays and heaters was developed to maintain primary system pressure within bounds. Further, the model has been developed to allow the user to input beginning-, middle-, or end-of-cycle reactivity conditions.

Three simulations were run that demonstrate the capability of the model controllers to meet target parameters while preserving system values within reasonable bounds. The first simulation is an initialization study at 160 MW(thermal)/50 MW(electric) that compares the model steady-state values with the design certification values. This simulation demonstrates the capability of the model to operate in natural circulation mode and closely matches operating values set forth in the NRC design certification documents. The second simulation is a power uprate from 160 MW(thermal)/50 MW(electric) to 200 MW(thermal)/60 MW(electric), and the final simulation is of a typical summer day where the turbine demand oscillates throughout the day. These illustrate the capabilities of the system to operate under natural circulation while maintaining system parameters within controller bounds and to match turbine output with turbine demand.

This work adds a systems-level model of the NuScale power module with associated control systems, reactivity coefficients, control banks, coolant through fuel temperature profiles, and associated mass flow rates throughout the system that have been added to the Modelica ecosystem. This model will be the basis of work that is utilized in the Joint Use Modular Plant program at INL, which proposes to utilize a single power module to support research, development, and demonstration activities, with a specific aim to demonstrate various IES configurations. As part of the ecosystem, the NuScale module can be quickly integrated with existing Modelica modules (e.g., thermal energy storage, reverse osmosis, high-temperature steam electrolysis, gas turbines) to model energy grids in different geographical locations.

摘要

本文概述了爱达荷州国家实验室（INL）的Modelica过程模型生态系统中NuScale功率模块的开发，该模块是美国能源部核能集成能源系统办公室（IES）计划的一部分。

模型开发导致以Modelica语言创建了动态NuScale模块，该模块在自然循环下运行，并且与核监管委员会（NRC）的设计认证文档中列出的设计参数相一致。已开发出与NuScale设计认证文件中提到的控制器一致的控制器。虽然特性时间常数可能会因控制器增益而有所不同，但系统的实际控制动作与NuScale规定的动作一致。除了自然循环和控制器外，NuScale电源模块还包括热通道计算，反应性控制和增压器。热通道计算包括散装流体温度，外部包层温度，燃料中心线温度以及偏离核沸腾率的数据。反应性控制结合了慢化剂和燃料温度反馈机制，硼浓度和控制库位置。开发了带有喷雾器和加热器的增压器，以将一次系统的压力保持在一定范围内。此外，已经开发了该模型以允许用户输入周期开始，中间或周期反应性条件。

运行了三个仿真，这些仿真演示了模型控制器满足目标参数的能力，同时将系统值保留在合理范围内。第一个模拟是在160 MW（热）/ 50 MW（电）下进行的初始化研究，将模型稳态值与设计认证值进行比较。该仿真演示了该模型在自然循环模式下运行的能力，并且与NRC设计认证文件中规定的运行值非常匹配。第二个模拟是将功率从160 MW（热）/ 50 MW（电）提升到200 MW（热）/ 60 MW（电），最后的模拟是在典型的夏季，其中涡轮机需求全天都在波动。

这项工作添加了NuScale功率模块的系统级模型，以及已添加到Modelica生态系统中的相关控制系统，反应系数，控制库，通过燃料温度曲线的冷却剂以及整个系统中的相关质量流率。该模型将成为INL联合使用模块化工厂计划中使用的工作基础，该计划提议利用单个电源模块来支持研究，开发和演示活动，其具体目的是演示各种IES配置。作为生态系统的一部分，NuScale模块可以与现有Modelica模块（例如，热能存储，反渗透，高温蒸汽电解，燃气轮机）快速集成，以对不同地理位置的能源网格进行建模。